I would think those springs are overkill for that camshaft you are running. I ran a 242/248 duration with .584"/.579" hydraulic roller with a single beehive spring. It was 130 seat and 313 open (going off the top of my head here). You are running 480lbs with less duration and less lift, probably a lobe rate similar to what I was running. If you are running heavy rockers or heavy valves then they might be necessary but I bet it would be fine with a 918 beehive spring.
My new cam is 256/260 with lift near .700" with heavy Crower maximus roller lifters, shaft rockers, and big pushrods, and my springs are similar to what you have right now.